linux-kernel - Re: [PATCH v3 0/2] Add LED driver for flash module in QCOM PMICs

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Message-Id: <CNPUQGP720NA.3KXP115T46HC@otso>
Date:   Wed, 19 Oct 2022 13:09:56 +0200
From:   "Luca Weiss" <luca.weiss@...rphone.com>
To:     "Fenglin Wu" <quic_fenglinw@...cinc.com>,
        <linux-arm-msm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <krzysztof.kozlowski@...aro.org>
Cc:     <quic_collinsd@...cinc.com>, <quic_subbaram@...cinc.com>
Subject: Re: [PATCH v3 0/2] Add LED driver for flash module in QCOM PMICs

Hi Fenglin,

On Wed Oct 19, 2022 at 12:17 PM CEST, Fenglin Wu wrote:
>
>
> On 2022/10/19 15:23, Luca Weiss wrote:
> > Hi Fenglin,
> > 
> > On Tue Oct 18, 2022 at 3:40 AM CEST, Fenglin Wu wrote:
> >> Initial driver and binding document changes for supporting flash LED
> >> module in Qualcomm Technologies, Inc. PMICs.
> >>
> > 
> > Thanks for these patches, it's really nice to see drivers like this
> > being sent upstream!
> > 
> > I've just tried these patches on pm6150l which also is compatible with
> > this driver (and used on sm7225-fairphone-fp4).
> > 
> > The two different flash LEDs on the device I could adjust as expected
> > using sysfs:
> > 
> > $ echo 255 > /sys/class/leds/yellow:flash-0/brightness
> > $ echo 255 > /sys/class/leds/white:flash-0/brightness
> > 
> > Also lower brightness values resulted in lower brightness on the LED, so
> > all is good here!
> > 
> > But for flash usage, I couldn't figure out how to use it, doing the
> > following resulted in no change on the LED.
> > 
> > $ cat /sys/class/leds/white:flash-0/max_flash_brightness
> > 1000000
> > $ echo 1000000 > /sys/class/leds/white:flash-0/flash_brightness
> > 
> > Here's my LED definition:
> > 
> >    led-0 {
> >      function = LED_FUNCTION_FLASH;
> >      color = <LED_COLOR_ID_YELLOW>;
> >      led-sources = <1>;
> >      led-max-microamp = <180000>;
> >      flash-max-microamp = <1000000>;
> >      flash-max-timeout-us = <1280000>;
> >    };
> > 
> >  From values are from msm-4.19 kernel:
> > 
> >    qcom,flash_0 {
> >      qcom,current-ma = <1000>; // => flash-max-microamp
> >      qcom,duration-ms = <1280>; // => flash-max-timeout-us
> >      qcom,id = <0>; // => led-sources?
> >    };
> > 
> >    qcom,torch_0 {
> >      qcom,current-ma = <180>; // => led-max-microamp
> >      qcom,id = <0>; // => led-sources?
> >    };
> > 
> > Could you please let me know how flash is supposed to work or if I
> > maybe have messed up some setting here?
> > 
> > Regards
> > Luca
>
> Hi Luca,
>
> Thanks for testing the driver at your end.
> The "brightness" node is for enabling/disable/adjusting brightness when 
> the LED is working in torch mode, the nodes for enabling/adjusting the 
> LED behavior in flash mode are "flash_brightness" "flash_timeout" 
> "flash_strobe".
> You can strobe the flash by "echo 1 > flash_strobe" directly and the 
> default brightness/timeout value will be used, or you can update the 
> settings with "echo xxx > flash_brightness; echo xxx > flash_timeout" 
> then strobe the LED with "echo 1 > flash_strobe". Please remember you 
> always need to "echo 0 > flash_strobe" 1st if you want to enable it again.
> Thanks

Indeed with flash_strobe it works as expected!

Tested-by: Luca Weiss <luca.weiss@...rphone.com> # sm7225-fairphone-fp4 + pm6150l

Thanks again,
Luca

>
> Fenglin
> > 
> >> Changes in V3:
> >>    1. Updated the driver to use regmap_field for register access.
> >>    2. Adressed the review comments in binding document change.
> >>
> >> Changes in V2:
> >>    1. Addressed review comments in binding change, thanks Krzysztof!
> >>    2. Updated driver to address the compilation issue reported by
> >>       kernel test robot.
> >>
> >>
> >> Fenglin Wu (2):
> >>    leds: flash: add driver to support flash LED module in QCOM PMICs
> >>    dt-bindings: add bindings for QCOM flash LED
> >>
> >>   .../bindings/leds/qcom,spmi-flash-led.yaml    | 116 +++
> >>   drivers/leds/flash/Kconfig                    |  15 +
> >>   drivers/leds/flash/Makefile                   |   1 +
> >>   drivers/leds/flash/leds-qcom-flash.c          | 700 ++++++++++++++++++
> >>   4 files changed, 832 insertions(+)
> >>   create mode 100644 Documentation/devicetree/bindings/leds/qcom,spmi-flash-led.yaml
> >>   create mode 100644 drivers/leds/flash/leds-qcom-flash.c
> >>
> >> -- 
> >> 2.25.1
> >